Question

What is the inverse of the function f(x) = 2x + 1?

Answer 1

Answer:  " f⁻¹(x) = (x-1)/2  ";  or, write as:

___________________________________

              " f⁻¹(x) = (x/2) - (1/2) " .

___________________________________

Step-by-step explanation:

___________________________________

Given:   f(x) = 2x + 1 ;  Find the inverse:

___________________________________

1)  Rewrite as y = 2x + 1 ;

2) Replace the "x" with "y" ; and the "y" with "x" ; and rewrite:

         x = 2y + 1 ;

3)  Now, "solve"; with "y" standing alone as a single, isolated variable on the left side of the equation, with an "equals" sign following the "y" :

         x = 2y + 1 :

Subtract "1" from each side of the equation:

         x - 1 = 2y + 1 - 1 ;

to get:

         x - 1 = 2y ;

___________________________________

↔  Rewrite as :

2y = x - 1 ;

Now, divide each side of the equation by "2" ;

  to isolate "y" on the left-hand side of the equation;

  & to solve in terms of "y":

___________________________________

2y / 2 = (x-1)/2 ;

___________________________________

to get:

y = (x-1)/2 ;

or; write as:  y = (x/2) - (1/2);

___________________________________

Now, rewrite; by replacing the "y" with "f⁻¹(x) "; as follows (to indicate that this is the "inverse function"):

___________________________________

f⁻¹(x) = (x-1)/2 ;  or, write as:

___________________________________

f⁻¹(x) = (x/2) - (1/2) .

___________________________________

Hope this is helpful to you!

 Best wishes!

___________________________________

Answer 2

Answer:

$f^{-1}$ (x) = $\frac{x-1}{2}$

Step-by-step explanation:

let y = f(x) and rearrange making x the subject, that is

y = 2x + 1 ( subtract 1 from both sides )

y - 1 = 2x ( divide both sides by 2 )

$\frac{y-1}{2}$ = x

Change y back into terms of x with x = $f^{-1}$ (x) , so

$f^{-1}$ (x) = $\frac{x-1}{2}$